by

Etymology

From Middle English by, bi, from Old English bī (“by; near; around”), from Proto-West Germanic *bī, from Proto-Germanic *bi (“near; by; around; about”), from Proto-Indo-European *h₁epi. Cognate with West Frisian by (“by; near”), Afrikaans by (“at; by; near”), Saterland Frisian bie (“near; by”), Dutch bij (“near; by”), German Low German bi (“by; near; at”), German bei (“by; near; at”).

prep

1. Near or next to.
   The mailbox is by the bus stop.
2. From one side of something to the other, passing close by; past.
   The stream runs by our back door.
   He ran straight by me.
3. Not later than (the given time); not later than the end of (the given time interval).
   Be back by ten o'clock!.
   We'll find someone by the end of March.
   We will send it by the first week of July.
4. Indicates the person or thing that does or causes something: Through the action or presence of.
   1. Following a passive verb.
      The matter was decided by the chairman.
      The boat was swamped by the water.
      He was protected by his body armour.
      Valencia threatened sporadically in the first half with Miguel having a decent effort deflected wide by Ashley Cole, while Jordi Alba's near-post cross was flicked into the sidenetting by Pablo Hernandez. September 28, 2011, Jon Smith, “Valencia 1-1 Chelsea”, in BBC Sport
   2. Following a noun.
      There was a call by the unions for a 30% pay rise.
   3. (not in common modern use) Following an adjective.
      I was aghast by what I saw.
      In other directions the fields and sky were so much of one colour by the snow that it was difficult in a hasty glance to tell whereabouts the horizon occurred […]. 1874, Thomas Hardy, Far from the Madding Crowd, 2005 Barnes & Noble Classics publication of 1912 Wessex edition, p.109
5. Indicates the creator of a work: Existing through the authorship etc. of.
   There are many well-known plays by William Shakespeare
6. Indicates a means of achieving something: Involving/using the means of.
   I avoided the guards by moving only when they weren't looking.
   By Pythagoras' theorem, we can calculate the length of the hypotenuse.
   We went by bus.
   I discovered it by chance.
   By 'maybe' she means 'no'.
   The electricity was cut off, so we had to read by candlelight.
   Players: Can we get there by candlelight? ¶ Gatekeepers: Yes and back again. 1945, Neva L. Boyd, Handbook of Recreational Games, Dover, published 1975, page 16
   By the light of the moon, / by the light of a star / they walked all night 1960, Dr. Seuss, One Fish Two Fish Red Fish Blue Fish
7. Indicates an authority according to which something is done.
   By the power vested in me, I now pronounce you man and wife.
   1. Invokes an authority in an oath.
      By Jove! I think she's got it!
      By all that is holy, I'll put an end to this.
      'By my soul! I believe something bad has happened me,' he muttered, and popped up his window, and looked out, half dreaming over the church-yard on the park beyond […] 1863, Sheridan Le Fanu, The House by the Churchyard
8. Indicates a means of classification or organisation.
   I sorted the items by category.
   Table 1 shows details of our employees broken down by sex and age.
9. Indicates the amount of change, difference or discrepancy
   Our stock is up by ten percent.
   His date of birth was wrong by ten years.
10. In the formulae X by X and by Xs, indicates a steady progression, one X after another.
    We went through the book page by page.
    We crawled forward by inches.
11. (with the) Acted on in units of the specified size or measure. (Sometimes hyperbolically)
    sold by the yard; cheaper if bought by the gross
    He drinks brandy by the bucketful!
12. per; with or in proportion to each.
    His health was deteriorating by the day.
    The pickers are paid by the bushel.
13. Indicates a referenced source: According to.
    He cheated by his own admission.
    By my reckoning, we should be nearly there.
    Ignorant and ſuperſtitious wretches meaſure the actions of letterd and philoſophical men by the tattle of their nurſes or illiterate parents and companions, or by the faſhion of the country : and people of differing religions judge and condemn each other by their own tenents ; when both of them cannot be in the right, and it is well if either of them are. 1722, William Wollaston, “Sect. V. Truths relating to the Deity. Of his exiſtence, perfection, providence, &c.”, in The Religion of Nature Delineated, page 81
14. Used to separate dimensions when describing the size of something.
    It is easy to invert a 2-by-2 matrix.
    The room was about 4 foot by 6 foot.
    The bricks used to build the wall measured 10 by 20 by 30 cm.
15. (horse breeding) Designates a horse's male parent (sire); cf. out of.
    She's a lovely little filly, by Big Lad, out of Damsel in Distress.

adv

1. Along a path which runs past the speaker.
   I watched as it passed by.
2. In the vicinity, near.
   There was a shepherd close by.
3. To or at a place, as a residence or place of business.
   I'll stop by on my way home from work.
   We're right near the lifeguard station. Come by before you leave.
4. Aside, away.
   The women spent much time after harvest putting jams by for winter and spring.

adj

1. Out of the way, off to one side.
   a by path, a by room
2. Subsidiary, incidental.
   by catch, a by issue

noun

1. Alternative form of bye.

intj

1. Dated form of bye (“goodbye”)..